Electrocochleographic study of Ménière's disease (author's transl)

Abstract

Meniere's disease is a disorder of both the peripheral auditory and vestibular systems.Although a considerable amount of studies has been performed on the function of both systems in Meniere's disease, there is little informations on the function of the peripheral auditory system. Electrocochleography makes it possible to measure human cochlear potentials for the study of the function of the cochlea. The action potential (AP) of 8 th nerve, the cochlear microphonics (CM) and summating potential (SP) were used as indicators for the function of the peripheval auditory system. They were recorded through a meatal skin surface electrode. An average response computor was employed. Acoustic stimuli were clicks and pure tone bursts between 0.5 kHz and 8 kHz. They were delivered to the human ear in u free field.The electrocochleographic examinations were performed on 17 ears of involved site of Meniere's disease, 13 ears with normal hearing and 35 ears with sensorineural hearing loss without dizzines. It was physiologically proved that a clickevoked inner ear potential after cancellation of CM was consisted of AP and SP.AP, SP compound potential recorded from Meniere's disease group had characteristics of a broad wave form, a large negative SP and abrupt increasing of N1 amplitude in high click intensity.This distortion of wave form of AP, SP compound potential was evaluated by measuring its width on base line and its SP/AP ratio. It was stastically significant that values of these parameters in Meniere's disease group was larger than in other two groups. (p<0.01)These results made it possible to diagnose Meniere's disease by the cochlear examination without vestibular examination.Diagnostic criteria of Meniere's disease based on electrocochleographic examination were as follows1. subjective symptome; episodic vertigo, hard of hearing and tinnitus.2. objective findings; SP/AP ratio is more than 0.43 under click intensity more than 81 dB.3. no neurological disorders except 8th nerve.All these conditions must be satisfied in order to obtain diagnosis of Meniere's disease.